The present invention relates to an improved valve assembly and method for starting an engine with a minimal amount of electrical power.
Auxiliary power units are commonly utilized in conjunction with aircraft engines to drive various equipment, including generators to supply auxiliary power. These auxiliary power units may include a turbine engine which is operated on fuel which is a mixture of gaseous oxygen and a liquid hydrocarbon fuel, such as JP-4 or the equivalent. It is relatively difficult to start the engine in an auxiliary power unit when the ambient temperature is very cold, for example -56.degree. F. At very low temperatures, a battery which is normally used in the starting of the engine in the auxiliary power unit is almost powerless. Therefore, alternative sources of power, such as batteries which are maintained in a heated environment, must be used in conjunction with the starting of the auxiliary power unit.